Opened 4 years ago
Closed 3 years ago
#15201 closed defect (fixed)
Problem with Hecke eigenvalues with the same index as the level
Reported by:  fstromberg  Owned by:  

Priority:  major  Milestone:  sage6.2 
Component:  modular forms  Keywords:  
Cc:  Merged in:  
Authors:  Alex Ghitza  Reviewers:  Peter Bruin 
Report Upstream:  N/A  Work issues:  
Branch:  56341a3 (Commits)  Commit:  56341a3580c8f63a7e5b32e34325e23b021efc99 
Dependencies:  Stopgaps: 
Description (last modified by )
It seems to be a problem to compute Hecke eigenvalues for Modular Symbol subspaces at integers dividing the level N unless the eigenvalue for the Hecke operator at N is computed first. I have verified this problem for sage versions between 5.8 and 5.12.beta.
Example
sage: M=ModularSymbols(5,6,sign=1) sage: S=M.decomposition() sage: f=S[0] sage: f.eigenvalue(10) IndexError Traceback (most recent call last) ... IndexError: n must be a positive integer sage: f.eigenvalue(5) 25 sage: f.eigenvalue(10) 50
Change History (7)
comment:1 Changed 3 years ago by
 Milestone changed from sage6.1 to sage6.2
comment:2 Changed 3 years ago by
 Description modified (diff)
comment:3 Changed 3 years ago by
comment:4 Changed 3 years ago by
 Branch set to u/AlexGhitza/ticket/15201
 Created changed from 09/16/13 00:00:39 to 09/16/13 00:00:39
 Modified changed from 04/24/14 14:02:50 to 04/24/14 14:02:50
comment:5 Changed 3 years ago by
 Commit set to 56341a3580c8f63a7e5b32e34325e23b021efc99
 Status changed from new to needs_review
New commits:
56341a3  fix Hecke eigenvalues recurrence

comment:6 Changed 3 years ago by
 Component changed from number theory to modular forms
 Reviewers set to Peter Bruin
 Status changed from needs_review to positive_review
comment:7 Changed 3 years ago by
 Branch changed from u/AlexGhitza/ticket/15201 to 56341a3580c8f63a7e5b32e34325e23b021efc99
 Resolution set to fixed
 Status changed from positive_review to closed
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The code used the recursive formula for the Hecke eigenvalues of ppower index without implementing the base case. This is fixed in the attached branch.